(5R)-5-hydroxytriptolide inhibits the immune response of human peripheral blood mononuclear cells.
OBJECTIVE
(5R)-5-hydroxytriptolide (LLDT-8) displayed immunosuppressive activities both in vitro and in autoimmune disease models. Here, we aim to further clarify the effect of LLDT-8 on the immune responses of human peripheral blood mononuclear cells (PBMC).


METHODS
Cell proliferation of human PBMC from healthy donors was evaluated by [3H]-thymidine uptake. NK cell cytotoxicity was assayed using K562 cells in a [3H] lysis assay. Cytokine production was determined by enzyme-linked immunosorbent assay. The expression of cell surface molecules was detected with flow cytometry. The mRNA expression and the protein phosphorylation levels were detected by RT-PCR and Western immunoblot assay.


RESULTS
LLDT-8 at 25 and 50 nM significantly inhibited the PHA- and recall antigens-induced T cell proliferation, and suppressed mixed lymphocyte reaction. LLDT-8 reduced cytokines production (IFN-gamma, IL-2, TNF-alpha) in PHA- and Sac-activated PBMC. LLDT-8 did not alter the increased expression of MHC class I/II and B7.1, but reduced B7.2 by approximately 30%. No effect of LLDT-8 was observed for the expression of T cell activation markers (CD69, CD154). However, LLDT-8 significantly reduced IFN-gamma-expressing T cell percentages and IFN-gamma mRNA transcription in PHA-activated T cells. It also inhibited the phosphorylation levels of JNK and p38. LLDT-8 did not affect NK cytotoxic activity against K562 cells.


CONCLUSIONS
LLDT-8 was a promising immunosuppressant for human immune-related diseases.
Zhou
Ru
R
Laboratory of Immunopharmacology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, PR China.
Tang
Wei
W
He
Pei-Lan
PL
Yang
Yi-Fu
YF
Li
Yuan-Chao
YC
Zuo
Jian-Ping
JP
D000938:Antigen-Presenting Cells / Q000187:drug effects; D015153:Blotting, Western; D049109:Cell Proliferation / Q000187:drug effects; D016207:Cytokines / Q000096:biosynthesis; D004224:Diterpenes / Q000494:pharmacology*; D005434:Flow Cytometry; D005805:Genes, MHC Class I / Q000187:drug effects; D005802:Genes, MHC Class II / Q000187:drug effects; D006801:Humans; D007111:Immunity, Cellular / Q000187:drug effects*; D007166:Immunosuppressive Agents; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000096:biosynthesis; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects; D007959:Lymphocyte Culture Test, Mixed; D020928:Mitogen-Activated Protein Kinases / Q000096:biosynthesis; D009000:Monocytes / Q000187:drug effects* / Q000276:immunology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000187:drug effects; D013778:Tetrazolium Salts; D013844:Thiazoles
C509074:5-hydroxytriptolide; D016207:Cytokines; D004224:Diterpenes; D007166:Immunosuppressive Agents; D013778:Tetrazolium Salts; D013844:Thiazoles; D007371:Interferon-gamma; D020928:Mitogen-Activated Protein Kinases; C022616:thiazolyl blue